1. Field of the Invention
This invention relates to block tongs and more particularly to a multi-unit block tong assembly which may be used to lift and transport large building blocks such as those used in retaining walls, steps, etc.
2. Description of the Related Art
Brick tongs have been used for many years to enable a workman to carry a plurality of bricks from a source of supply to a work site. The conventional brick tongs comprise plates or hooks disposed at ends of a pair of pivoting arms designed so that when the tongs are lifted, the plates or hooks are moved into engagement with the ends of the outermost bricks so that the bricks are firmly grasped to enable the bricks to be lifted and carried. During the past several years, large concrete blocks have been fabricated for use in retaining walls, steps, etc. The blocks are quite large and heavy and are difficult for a workman to move from a pallet or the like to the job site.
In the past, applicant devised a multi-unit concrete block tong assembly wherein the block tongs could lift and carry a plurality of concrete blocks from a pallet to the job site with the block tongs being supported from the end of a boom mounted on a skid-steer loader or the like. Although the block tongs of applicant""s previous device did perform satisfactorily, the previous device required the presence of a worker to permit the block tongs to be selectively locked into the open position so that the tongs could be mounted on the concrete blocks and so that the block tongs could be removed from the concrete blocks once the blocks were properly positioned adjacent the job site.
A multi-unit concrete block tong assembly is provided which includes three top tubes pivotally connected at one end thereof to one end of three bottom tubes. A lifting apparatus is operatively connected to the three top tubes whereupon upward movement of the three top tubes by the lifting device will cause the top tubes to pivot with respect to the bottom tubes. A front plate is secured to one end of each of the top tubes for movement therewith. A back plate is longitudinally adjustably secured to each of the bottom tubes adjacent the other end thereof. A solenoid operated dead bolt is selectively movably mounted within each of the top tubes and is movable between extended and retracted positions. A spring is positioned within each of the top tubes for moving the dead bolt therein to its extended position. The solenoid is operatively connected to each of the dead bolts for moving the dead bolt from its extended position to its retracted position. An upstanding support is provided on each of the bottom tubes adapted to receive the dead bolt of the associated top tube to lock the assembly in its open position. When the solenoids are activated, the dead bolts are retracted into the top tubes so that when the lifting device raises the assembly, the top tubes pivot with respect to the bottom tubes to urge the front plates and back plates of the assembly into frictional engagement with the ends of the concrete blocks.
It is therefore a principal object of the invention to provide an improved multi-unit concrete block tong assembly.
A further object of the invention is to provide a multi-unit concrete block tong assembly which includes a solenoid operated dead bolt designed to lock the assembly in its open position, thereby eliminating the need for the presence of a worker.
A further object of the invention is to provide a concrete block tong assembly which is designed to lift and carry a plurality of concrete blocks.
A further object of the invention is to provide a concrete block tong assembly including means for rotating the same to properly position the assembly with respect to the concrete blocks to be lifted and carried and to permit the concrete blocks to be properly positioned within or at the job site.
These and other objects will be apparent to those skilled in the art.